Solar Cell Module Connector

ABSTRACT

The present invention includes two pairs of positive and negative cables are led out by dividing a pair of positive and negative terminals of a solar cell modules, and dipole connectors to which terminals are connected are formed on ends of the cables. The terminals in the dipole connector disposed on one side of the solar cell module form positive and negative plugs, while the terminals in the other dipole connector disposed on the other side of the solar cell module form positive and negative sockets. The cables include an inverse connection preventing portion which allows connection between the dipole connectors on a plug and socket side disposed between each adjacent solar cell modules when the polarities of the negative and positive terminals are the same, but which restricts connection therebetween when the polarities of the negative and positive terminals differ from each other.

TECHNICAL FIELD

The present invention relates to a solar cell module connector used toconnect a plurality of solar cell modules.

BACKGROUND ART

A solar power generation system supplies direct currents from a solarcell panel installed on a house roof to electric appliances via a devicesuch as an inverter. The solar cell panel is constituted by a pluralityof solar cell modules which are connected to each other via connectorsconnected to ends of cables.

A solar power generation system formed by connecting a plurality ofsolar cell modules in parallel with each other is known (see, forexample, patent document 1 shown below). A solar power generation systemof this kind has a structure in which, as shown in FIG. 17A, a pair ofpositive and negative cables 2 and another pair of positive and negativecables 2 diverging from a pair of positive and negative terminals of asolar cell module 1 are led out, positive connectors 3 and negativeconnectors 4 are attached to ends of the cables 2, and, as shown in FIG.17B, the positive connector 3 of this solar cell module 1 is connectedto the positive connector 3 of an adjacent solar cell module 1 and thenegative connector 4 of this solar cell module 1 is connected to thenegative connector 4 of the adjacent solar cell module 1, thussuccessively connecting solar cell modules 1.

In this case, the positive connectors 3 and the negative connectors 4comprise plugs (denoted by “P” in the figure) and sockets (denoted by“S” in the figure), and one combination of a plug and a socket areprovided on opposite side of each solar cell module 1. If a plurality ofsolar cell modules 1 arranged in the direction of connectionstherebetween (the horizontal direction in FIG. 17B) is assumed to be onegroup, the solar power generation system 1 is divided into a pluralityof groups (in the top-bottom direction of FIG. 17B) and output terminalsfrom the groups are combined and connected to a power conditioner or thelike.

[Patent document 1] Japanese Patent Laid-Open No. 8-46231

In the above-described case, the positive connectors 3 are formed so asto be identical in shape and size to each other; the negative connectors4 are also formed so as to be identical in shape and size to each other;and the plugs and sockets are positioned close to each other in eachadjacent upper-lower pair of the groups, as indicated by arrows in FIG.17B. Therefore, there is a possibility of a connection being erroneouslymade between the positive and negative terminals in each group as wellas between the groups.

The present invention has been completed in view of the above-describedcircumstances, and an object of the present invention is to avoid theoccurrence of an erroneous connection between connectors not to be matedwith each other.

DISCLOSURE OF THE INVENTION

The invention set forth in claim 1 as a means for achieving theabove-described object is characterized by having a plurality of solarcell modules connected in parallel with each other, pairs of positiveand negative cables led out by dividing a pair of positive and negativeterminals of each of the solar cell modules, positive and negative plugswhich are terminals connected to ends of the cables, and which aredisposed on one side of each solar cell module, positive and negativesockets which are terminals also connected to ends of the cables, whichare disposed on the other side of each solar cell module, and which canbe respectively connected to the plugs, a plug-side dipole connectorincluding the positive and negative plugs and formed at the ends of thecables, the plug-side dipole connector for connecting the plugs disposedon one side of one of the solar cell modules to the sockets disposed onthe other side of another of the solar cell modules adjacent to the oneof the solar cell modules, a socket-side dipole connector including thepositive and negative sockets and formed at the ends of the cables, thesocket-side dipole connector for connecting to the plugs disposed on oneside of one of the solar cell modules the sockets disposed on the otherside of another of the solar cell modules adjacent to the one of thesolar cell modules, and an inverse connection preventing portionprovided on the plug-side dipole connector and the socket-side dipoleconnector to enable connection between the two dipole connectors in acase where the polarities of the positive and negative terminals in eachcombination between the two dipole connectors are the same, and torestrict connection between the two dipole connectors in a case wherethe polarities of the positive and negative terminals in eachcombination between the two dipole connectors differ from each other.

The invention set forth in claim 2 is characterized in that, in thearrangement set forth in claim 1, the inverse connection preventingportion comprises projections projecting from surfaces of the plug-sidedipole connector and the socket-side dipole connector opposed to eachother, and in that the two projections are in a non-interfering state inthe case where the polarities of the positive and negative terminals ineach combination are the same, and collide against each other in thecase where the polarities of the positive and negative terminals in eachcombination differ from each other.

The invention set forth in claim 3 is characterized in that, in thearrangement set forth in claim 2, the dipole connector has a clamp forconnecting together the positive connector and the negative connectorconstituting the dipole connector, and the projection projects from anend surface of the clamp.

The invention set forth in claim 4 is characterized in that, in thearrangement set forth in claim 3, the clamp is constituted by a pair ofdivided members capable of pinching the positive connector and thenegative connector in a peripheral direction and divisible from eachother, and the projection is formed on only one of the divided members.

The invention set forth in claim 5 is characterized in that, in thearrangement set forth in claim 1, the inverse connection preventingportion comprises a flexible lock portion provided in one of theplug-side dipole connector and the socket-side dipole connector, and alock receiving portion provided on the other dipole connector, and inthat the lock portion is elastically engageable with the lock receivingportion only when the polarities of the positive and negative terminalsin each combination are the same and when the two dipole connectorsreach the normal connection position.

The invention set forth in claim 6 is characterized in that, in thearrangement set forth in claim 5, the lock portion and the lockreceiving portion are provided in only one of the positive and negativeconnectors constituting the dipole connector.

The invention set forth in claim 7 is characterized in that, in thearrangement set forth in claim 1, the inverse connection preventingportion comprises offset portions formed by shifting in the axialdirection the end positions of the positive connector and the negativeconnector constituting the dipole connector, and in that fitting betweenthe offset portions can be performed when the polarities of the positiveand negative terminals are the same, and cannot be performed when thepolarities of the positive and negative terminals differ from eachother.

The invention set forth in claim 8 is characterized in that, in thearrangement set forth in claim 7, the dipole connector has a clamp whichconnects together the positive connector and the negative connectorconstituting the dipole connector, and the offset portions are formed onthe basis of a stepped form of the clamp.

<Claim 1>

The dipole connectors are connected to ends of cables led out from thepair of positive and negative terminals of each solar cell module, theterminals in the dipole connector disposed on one side of the solar cellmodule form positive and negative plugs, and the terminals in the dipoleconnector disposed on the other side of the solar cell module formpositive and negative sockets. In a case where a plurality of solar cellmodules aligned with each other in row and column directions areconnected in parallel with each other to form one group in a horizontaldirection for example, the two dipole connectors opposed to each otherin the column direction are in a plug-to-plug relationship or in asocket-to-socket relationship. Therefore, the occurrence of erroneousconnection between the two dipole connectors between groups can beavoided.

The plug-side dipole connector and the socket-side dipole connector hasan inverse connection preventing portion for restricting connection in acase where the polarities of the positive and negative terminals incombination between the two dipole connectors differ from each other.Therefore, the occurrence of erroneous connection between the two dipoleconnectors opposed to each other in the horizontal direction in eachgroup can also be avoided.

<Claim 2>

The inverse connection preventing portion comprises projections. Twoprojections are in a non-interfering state in a case where thepolarities of the positive and negative terminals are the same, andcollide against each other in a case where the polarities of thepositive and negative terminals differ from each other. Thus, inverseconnection between the two dipole connectors in each group can beprevented with reliability by a comparative simple method.

<Claim 3>

The projections project from end surfaces of the clamps (surfaces of theplug-side dipole connector and the socket-side dipole connector opposedto each other). Therefore, prevention of inverse connection can beachieved without changing the structures of the existing positive andnegative connectors.

<Claim 4>

The clamp is constituted by a pair of divided members and the projectionis formed on only one of the divided members. Therefore, the structureof one of the two divided members can be simplified.

<Claim 5>

The inverse connection preventing portion comprises a flexible lockportion provided in one of the plug-side dipole connector and thesocket-side dipole connector, and a lock receiving portion provided onthe other dipole connector, and the lock portion is elasticallyengageable with the lock receiving portion only when the polarities ofthe positive and negative terminals in each combination are the same andwhen the two dipole connectors reach the normal connection position.Therefore, the function to lock the two dipole connectors can include aninverse connection prevention function.

<Claim 6>

The lock portion and the lock receiving portion are provided in only oneof the positive and negative connectors constituting the dipoleconnector. Therefore, the need to provide a lock structure on the otherconnector can be eliminated to simplify the structure.

<Claim 7>

The inverse connection preventing portion comprises offset portionsformed by shifting in the axial direction the end positions of thepositive connector and the negative connector constituting the dipoleconnector, and fitting between the offset portions can be performed onlywhen the polarities of the positive and negative terminals are the same.Therefore, it is not necessary to add a separate member for preventionof inverse connection to the dipole connector. Simplification of thestructure can be achieved in this way.

<Claim 8>

The offset portions are formed on the basis of a stepped form of theclamp. Therefore, prevention of inverse connection can be achievedwithout changing the structure of the existing positive and negativeconnectors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a state in which a connector according toEmbodiment 1 of the present invention is connected to positive andnegative terminals of a solar cell module;

FIG. 2 is a side view of the connectors before connection;

FIG. 3 is a side view of the connectors connected together;

FIG. 4 is a sectional view of the connectors before connection;

FIG. 5 is a sectional view of the connectors connected together;

FIG. 6 is a front view of the connector on the socket side;

FIG. 7 is a front view of the connector on the plug side;

FIG. 8 is a wiring diagram showing a state in which a plurality of solarcell modules are connected in parallel with each other;

FIG. 9 is a side view of connectors before connection in Embodiment 2 ofthe present invention;

FIG. 10 is a side view of the connectors connected together;

FIG. 11 is a front view of the connector on the socket side;

FIG. 12 is a front view of the connector on the plug side;

FIG. 13 is a side view of connectors before connection in Embodiment 3of the present invention;

FIG. 14 is a side view of the connectors connected together;

FIG. 15 is a front view of the connector on the socket side;

FIG. 16 is a front view of the connector on the plug side;

FIG. 17A is a diagram schematically showing a state in which connectorsare connected to ends of two pairs of positive and negative cables inthe conventional art; and

FIG. 17B is a wiring diagram showing a state in which a plurality ofsolar cell modules are connected in parallel with each other in theconventional art.

DESCRIPTION OF SYMBOLS

-   11 Cable-   20 Dipole connector-   21 Positive connector-   22 Negative connector-   23 Clamp-   24 Fitting tubular portion-   27 Lock portion-   28 Lock lug-   31 Hood portion-   32 Lock receiving portion-   37 Projection

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

Embodiment 1 of the present invention will be described with referenceto FIGS. 1 to 8. In this embodiment, two pairs of positive and negativecables 11, i.e., one pair of positive and negative cables 11 and anotherpair of positive and negative cables 11, are led out by dividing a pairof positive and negative terminals from a solar cell module 10, and adipole connector 20 having terminals 15 connected to ends of the cables11 led out is integrally formed. A plurality of solar cell modules 10are disposed in matrix form, i.e., in alignment with each other in rowand column directions, and are connected in parallel with each other.

A terminal box 16 is attached to the back surface (the surface oppositefrom the glass surface) of the solar cell module 10, as shown in FIG. 1.A pair of positive and negative leads (not shown) from the solar cellmodule 10 are led into the terminal box 16 through an opening 17. Endsof the leads are connected to pairs of positive and negative relayterminals 18 in the terminal box 16. The cables 11 are connected to therelay terminals 18 and are extended as separate pairs of positive andnegative cables in opposite directions from left and right side walls 19of the terminal box 16. Terminals 15 are connected to the extension endsof the cables 11. Each pair of positive and negative terminals 15 areconnected to a corresponding pair of positive and negative connectors 21and 22, and the pair of connectors 21 and 22 are integrally combinedwith each other by a clamp 23, thus forming left and right pairs ofdipole connectors 20.

In the terminals 15 connected to the extension ends of the cables 11,each of the positive and negative ones in one of the left and rightpairs of dipole connectors 20 (disposed on the right-hand side of theterminal box as viewed in FIG. 1) is a plug (denoted by “P” in FIG. 8),while each of the positive and negative ones in the other of the leftand right pairs of dipole connectors 20 (disposed on the left-hand sideof the terminal box as viewed in FIG. 1) is a socket (denoted by “S” inFIG. 8).

As shown in FIG. 2 on the right-hand side and in FIG. 6, the other ofthe dipole connector 20 is constituted by the positive connector 21 andthe negative connector 22 on the socket side and the clamp 23 connectingtogether these connectors in parallel with each other. The positiveconnector 21 and the negative connector 22 are formed so as to beidentical in shape and size to each other.

Each of the positive connector 21 and the negative connector 22 on thesocket side has a fitting tubular portion 24 coaxially surrounding acylindrical socket and made of a synthetic resin, and a root portion ofthe socket is attached to an inner wall of the fitting tubular portion24. Axial guide ribs 25 are formed on an outer peripheral surface of thefitting tubular portion 24 on left and right sides of the same by beingextended. A pair of left and right protuberant portions 26 are formed onthe outer peripheral surface of the fitting tubular portion 24 on leftand right sides and on the rear end side (cable 11 connection side) ofthe same. A pair of left and right lock portions 27 generally parallelto the outer peripheral surface of the fitting tubular portion 24 areformed so as to project frontward from front end surfaces of theprotuberant portions 26. The lock portions 27 are in cantilever form andare flexibly deformable radially. A lock lug 28 is formed projectingoutward on a front end portion of each lock portion 27. A seal groove 29in which a seal ring 30 is fitted is provided in each fitting tubularportion 24 at a position closer to the front end relative to theprotuberant portion 26.

As shown in FIG. 2 on the left-hand side and in FIG. 7, the one of thedipole connectors 20 is constituted by the positive connector 21 and thenegative connector 22 on the plug side and the clamp 23 connectingtogether these connectors in parallel with each other. The positiveconnector 21 and the negative connector 22 are formed so as to beidentical in shape and size to each other, as are those described above.

Each of the positive connector 21 and the negative connector 22 on theplug side is in the form of a cylinder as a whole and has a cylindricalhood portion 31 coaxially surrounding a cylindrical plug. A root portionof the plug is attached to an inner wall of the hood portion 31. Theinside diameter of the hood portion 31 is set to such a value that thefitting tubular portion 24 on the socket side can be tightly fitted.Guide channels 36 engageable with the guide rib 25 are formed in aninner peripheral surface of the hood portion 31 on left and right sidesof the same by being extended in the axial direction. The seal ring 30on the socket side is brought into close contact with the innerperipheral surface of the hood portion 31 to effect sealing.

A pair of left and right lock receiving portions 32 capable ofelastically engaging with the lock portion 27 on the socket side areformed in the hood portion 31 on left and right sides and on the frontend side of the same. Each lock receiving portion 32 is in the form of atunnel as a whole and has an escapement hole 33 formed therethrough inthe front-rear direction. The lock portion 27 can be passed through theescapement hole 33 while being elastically bent inwardly. A rear endsurface of each lock receiving portion 32 is formed as a receivingsurface 34 capable of elastically engaging with the lock lug 28 of thelock portion 27 at the time of normal fitting to the socket. Morespecifically, in the process of fitting the two dipole connectors 20 onthe plug and socket sides, the lock lugs 28 of the lock portions 27advance inside the escapement holes 33 of the lock receiving portions 32while being elastically bent. When the two dipole connectors 20 reachthe normally fitted position, the lock lugs 28 move apart from theescapement holes 33 and the lock portions 27 elastically restore theoriginal shape. Simultaneously, the lock lugs 28 face the receivingsurface 34 in the axial direction and lock the two dipole connectors 20in a disengagement stopped state. A setting is made to ensure that, inthe process of fitting the two dipole connectors 20, positioning in thecircumferential direction is performed by sliding the guide ribs 25 inthe guide channels 36 to enable engagement between the lock portion 27and the lock receiving portion 32.

The clamp 23 on the plug side is formed of a synthetic resin and has, asshown in FIG. 7, such a construction as to be divided into left andright divided members 35. The two divided members 35 have their jointedges 35A fitted to each other from the left and right sides while thepair of positive and negative connectors 21 and 22 are arranged in thelongitudinal direction to pitch and hold the two connectors 21 and 22therebetween. In this case, the two divided members 35 are jointed in aone-touch manner based on the elastic engagement action therebetween.

On a front end surface of the divided member 35 disposed on theleft-hand side as viewed in FIG. 7 in the two divided members 35, aprojection 37 is formed substantially at a central position in theheight direction so as to project frontward. The projection 37 isdisposed between the pair of positive and negative connectors 21 and 22and has a sectional shape elongated in the lateral direction. When thepair of positive and negative connectors 21 and 22 are pinched betweenthe two divided members 35, the front end positions of the twoconnectors 21 and 22 are aligned with each other and the front end ofthe projection 37 is set at a position recessed from the front endpositions of the two connectors 21 and 22.

The clamp 23 on the socket side has an internal structure different fromthat of the clamp 23 on the plug side but has an external formsubstantially identical in shape and size to that of the clamp 23 on theplug side. Also, the clamp 23 on the socket side is constituted by leftand right divided members 35 joinable to each other, as described above.On a front end surface of the divided member 35 disposed on theleft-hand side as viewed in FIG. 6 in the two divided members 35, aprojection 37 is formed substantially at a central position in theheight direction so as to project frontward. The projection 37 mayalternatively be provided on the front end surface of each of thedivided members 35 disposed on the right-hand sides as viewed in FIGS. 6and 7.

In a case where a group in which a plurality of solar cell modules 10are connected in parallel with each other is formed, that is, thosearranged horizontally as viewed in FIG. 8 in a plurality of solar cellmodules disposed in alignment with each other in row and columndirections form one group, the dipole connector 20 on the plug side andthe dipole connector 20 on the socket side are opposed to each other inthe horizontal direction between each adjacent pair of the solar cellmodules 1.0 in the group, as shown in FIGS. 2 and 4. In this case, when,as shown in FIG. 2, the two dipole connectors 20 are set in therespective normal connection attitudes, and when the polarities of theterminals facing each other in each combination are the same, the end ofthe projection 37 on the plug side is opposed to the front end surfaceof the divided member 35 on which no projection 37 exists in the clamp23 on the socket side, while the end of the projection 37 on the socketside is opposed to the front end surface of the divided member 35 onwhich no projection 37 exists in the clamp 23 on the plug side. Thus,the two projections 37 are in a non-interfering positional relationshipwith each other. Consequently, plug-socket connections can be madebetween the positive poles and between the negative poles.

In contrast, when one of the two dipole connectors 20 is in the invertedattitude, and when the polarities of the terminals facing each other ineach combination differ from each other, the end of the projection 37 onthe plug side and the end of the projection 37 on the socket side are insuch a positional relationship as to abut against each other, andplug-socket connection is impossible between the different polarities.

More specifically, between the positive connector 21 on the plug sideand the positive connector 21 on the socket side and between thenegative connector 22 on the plug side and the negative connector 22 onthe socket side (as shown in FIGS. 3 and 5), the fitting tubularportions 24 are normally fitted in the hood portions 31 to enable theplug to be inserted in the socket through the normal depth and to enablethe lock portions 27 and the lock receiving portions 32 to elasticallyengage with each other to complete locking. In contrast, between thepositive connector 21 on the plug side and the negative connector 22 onthe socket side and between the negative connector 22 on the plug sideand the positive connector 21 on the socket side, the two projections 37collide against each other to stop the plug from being inserted beforethe lock portions 27 and the lock receiving portions 32 elasticallyengage with each other.

Thus, according to this embodiment, the two dipole connectors 20disposed between an adjacent pair of solar cell modules 10 can beprevented from being connected in the inverted state. Since the inverseconnection prevention function is performed on the basis of the shapesof the clamps 23, it is not necessary to specially change the shapes ofthe pair of positive and negative connectors 21 and 22.

Further, because two dipole connectors 20 opposed in the columndirection between the groups are in a plug-to-plug or socket-to-socketrelationship, erroneous connection between two dipole connectors 20between the groups can be avoided.

Embodiment 2

Embodiment 2 of the present invention will be described with referenceto FIGS. 9 to 12. The forms of the dipole connectors 20 in Embodiment 2differ from those in Embodiment 1. In other respects, Embodiment 2 issubstantially the same as Embodiment 1. A redundant description inrelation to the description of Embodiment 1 will not be made. Structuralportions identical or corresponding to those in Embodiment 1 areindicated by the same reference numerals.

In Embodiment 2, the forms of the positive connector 21 and the negativeconnector 22 constituting each dipole connector 20 are made differentfrom each other to prevent inverse connection between the two dipoleconnectors 20 disposed between each adjacent pair of solar cell modules10. More specifically, a construction described below is provided. Asshown in FIG. 9 on the right-hand side and in FIG. 11, the protuberantportions 26 and the lock portions 27 in Embodiment 1 are formed on thepositive connector 21 on the socket side, but the protuberant portions26 and the lock portions 27 are not formed on the positive connector 22on the socket side. Also, as shown in FIG. 9 on the left-hand side andin FIG. 12, the lock receiving portions 32 in Embodiment 1 are formed onthe positive connector 21 on the plug side, but the lock receivingportions 32 are not formed on the positive connector 22 on the plugside. The projection 37 in Embodiment 1 is not provided on each of theclamps 23 on the plug and socket sides. Thus, the structures of thenegative connectors 22 on the plug and socket sides are simplified.

According to Embodiment 2, when the two dipole connectors 20 disposedbetween an adjacent pair of solar cell modules 10 are in the normalconnection attitudes, the plug is inserted in the socket through thenormal depth and the lock portions 27 elastically engage with the lockreceiving portions 32 with the completion of this insertion, as shown inFIG. 10, thus enabling locking of the two dipole connectors 20. When oneof the two dipole connectors 20 is in the inverted attitude, the lockportions 27 and the lock receiving portions 32 are in a non-interferingrelationship even after the plug has been inserted in the socket. Thetwo dipole connectors 20 are not locked in this case. That is, inverseconnection between the two dipole connectors 20 can be detectedaccording to the locked/nonlocked state of the two dipole connectors 20.The arrangement may alternatively be such that the protuberant portions26 and the lock portions 27 are provided in the negative connector 22 onthe socket side, while the lock receiving portions 32 are provided inthe negative connector 22 on the plug side. The arrangement mayalternatively be such that the protuberant portions 26 and the lockportions 27 are provided in the negative connector 22 on the plug side,while the lock receiving portions 32 are provided in the negativeconnector 22 on the socket side. Further, the arrangement mayalternatively be such that the protuberant portions 26 and the lockportions 27 are provided in the positive connector 21 on the plug side,while the lock receiving portions 32 are provided in the positiveconnector 21 on the socket side.

Embodiment 3

Embodiment 3 of the present invention will be described with referenceto FIGS. 13 to 16. The form of clamps 23 in the dipole connectors 20 inEmbodiment 3 differs from that in Embodiment 1. In other respects,Embodiment 3 is substantially the same as Embodiment 1. Structuralportions identical or corresponding to those in Embodiment 1 areindicated by the same reference numerals.

Embodiment 3 has the same positive connectors 21 and negative connectors22 as those in Embodiment 1, and pairs of connectors 21 and 22 arefitted in clamps 23 to prevent inverse connection between two dipoleconnectors 20 disposed between each adjacent pair of solar cell modules10. That is, as shown in FIG. 13, the clamp 23 on the plug side and theclamp 23 on the socket side in the clamps 23 in Embodiment 3 areidentical to each other, and each clamp 23 has a holding portion 41 onthe positive connector 21 side for holding the positive connector 21,and a holding portion 42 on the negative connector 22 side for holdingthe negative connector 22. The clamp 23 is constructed in such a mannerthat the two holding portions 41 and 42 extend in a directionperpendicular to the axial direction; the positions of the two holdingportions 41 and 42 are shifted from each other in the axial direction;and the upper and lower ends of the two holding portions 41 and 42 areconnected to each other by an intermediate connection portion 43extending in the axial direction.

As shown in FIGS. 15 and 16, the clamp 23 is constituted by a pair ofleft and right divided members 35, and the positive and negativeconnectors 21 and 22 are pinched by combining the two divided members35. When the two connectors 21 and 22 are held in the thus-constructedclamp 23 at a position generally at a center in the longitudinaldirection, the end positions of the two connectors 21 and 22 are shiftedfrom each other in the axial direction, thereby forming offset portions45 in stepped form on front end surfaces of the dipole connectors 20.More specifically, in the dipole connector 20 on the plug side, the endposition of the negative connector 22 is set frontward relative to theend position of the positive connector 21. In the dipole connector 20 onthe socket side, the end position of the positive connector 21 is setfrontward relative to the end position of the negative connector 22. Theamounts of positional shift on the plug and socket sides are setsubstantially equal to each other.

According to Embodiment 3, when the two dipole connectors 20 on the plugand socket sides disposed between each adjacent pair of solar cellmodules 10 are opposed to each other by being set in the respectivenormal connection attitudes, and when the polarity of the terminalsfacing each other in each combination are the same, as shown in FIG. 14,the two offset portions 45 formed on the two dipole connectors 20 are insuch a relationship as to fit to each other, thereby allowing the plugto be inserted in the socket through the normal depth. Thus, connectionbetween the two dipole connectors 20 is enabled. In contrast, when oneof the two dipole connectors 20 is in the inverted attitude, and whenthe polarities of the terminals facing each other in each combinationdiffer from each other, fitting between the two offset portions 45 isrestricted to restrict the connection between the two dipole connectors20. Since this inverse connection prevention function is performed onthe basis of the shapes of the clamps 23, it is not necessary tospecially change the shapes of the pair of positive and negativeconnectors 21 and 22.

Other Embodiments

The present invention is not limited to the above-described embodiments.For example, embodiments described below are included in the technicalscope of the present invention, and various changes other than thosedescribed below may be made and implemented without departing from thescope of the invention.

-   (1) While projections are provided as inverse connection preventing    portions on the clamps in Embodiment 1 described above, a projection    may be provided as an inverse connection preventing portion on one    of the two positive and negative connectors according to the present    invention.-   (2) While each dipole connector is constituted by a pair of positive    and negative connectors to which terminals are attached and a clamp    in Embodiments 1 to 3, each dipole connector may be formed by    integrally forming a pair of positive and negative connectors from a    synthetic resin material without using a clamp according to the    present invention described above.

1-8. (canceled)
 9. A solar cell module connector comprising: a pluralityof solar cell modules connected in parallel with each other; a pair ofpositive and negative cables extending from at least two sides theplurality of solar cell modules; positive and negative plugs extendingfrom ends of the cables and disposed on one side of each of theplurality of solar cell modules; positive and negative sockets extendingfrom ends of the cables and disposed on the other side of each of theplurality of solar cell modules, and which can be respectively connectedto the plugs; a plug-side dipole connector including the positive andnegative plugs, the plug-side dipole connector for connecting the plugsdisposed on one side of one of the solar cell modules to the socketsdisposed on the other side of another of the solar cell modules adjacentto the one of the plurality of solar cell modules; a socket-side dipoleconnector including the positive and negative sockets, the socket-sidedipole connector for connecting to the plugs disposed on one side of oneof the solar cell modules the sockets disposed on the other side ofanother of the solar cell modules adjacent to the one of the pluralityof solar cell modules; and an inverse connection preventing portionprovided on the plug-side dipole connector and the socket-side dipoleconnector to enable connection between the plugs and sockets that havethe same polarity, and to restrict connection between the plugs andsockets having a different polarity.
 10. The solar cell module connectoraccording to claim 9, wherein the inverse connection preventing portionincludes projections projecting from surfaces of the plug-side dipoleconnector and the socket-side dipole connector opposed to each other,further wherein the projections are in a non-interfering state in thecase where the polarities of the plugs and sockets to be connected arethe same, and collide against each other in the case where thepolarities of the plugs and sockets to be connected differ from eachother.
 11. The solar cell module connector according to claim 10,wherein each of the plug-side and socket-side dipole connector has aclamp for connecting together a positive connector and a negativeconnector of each of the plug-side and socket side dipole connector,further wherein the projection extend from an end surface of the clamp.12. The solar cell module connector according to claim 11, wherein theclamp includes a pair of divided members capable of pinching thepositive connector and the negative connector in a peripheral directionand divisible from each other, and the projection is formed on only oneof the divided members.
 13. The solar cell module connector according toclaim 9, wherein the inverse connection preventing portion includes aflexible lock portion provided in one of the plug-side dipole connectorand the socket-side dipole connector, and a lock receiving portionprovided on the other dipole connector, further wherein the lock portionis elastically engageable with the lock receiving portion only when thepolarities of the plugs and sockets are the same.
 14. The solar cellmodule connector according to claim 9, wherein the inverse connectionpreventing portion includes offset portions formed by shifting in theaxial direction end positions of each of the positive and negative plugsand each of the positive and negative sockets, further wherein fittingbetween the offset portions can be performed when the polarities of theplugs and sockets are the same, and cannot be performed when thepolarities of the plugs and sockets differ from each other.
 15. Thesolar cell module connector according to claim 14, wherein each of theplug-side and socket-side dipole connector has a clamp, and the offsetportions are formed as stepped from the clamp.
 16. A connector systemcomprising: a first cable extending from a side of a first connector,the first cable including a plug-side dipole connector having a positiveand negative plug extending from an end of the first cable; a secondcable extending from a side of a second connector, the second cableincluding a socket-side dipole connector having a positive and negativesocket extending from an end of the second cable, wherein sockets arecapable of connection to the plugs; an inverse connection preventingportion provided on the plug-side dipole connector and the socket-sidedipole connector to enable connection between the plugs and sockets thathave a same polarity, and to restrict connection between the plugs andsockets having a different polarity.
 17. The connector system accordingto claim 16, wherein the inverse connection preventing portion includesprojections extending from a surface of the plug-side dipole connectorand a surface of the socket-side dipole connector, further wherein theprojections are in a non-interfering state when the polarities of theplugs and sockets to be connected are the same, and collide against eachother when the polarities of the plugs and sockets to be connecteddiffer from each other.
 18. The connector system according to claim 17,wherein each of the plug-side and socket-side dipole connector include aclamp for connecting together a positive connector and a negativeconnector of each of the plug-side and socket side dipole connector,further wherein the projection extends from an end surface of the clamp.19. The connector system according to claim 18, wherein the clampincludes a pair of divided members capable of pinching the positiveconnector and the negative connector in a peripheral direction
 20. Theconnector system according to claim 19, wherein the divide members aredivisible from each other.
 21. The connector system according to claim19, wherein the projection is formed on only one of the divided members.22. The connector system according to claim 16, wherein the inverseconnection preventing portion includes a flexible lock portion providedin one of the plug-side dipole connector and the socket-side dipoleconnector, and a lock receiving portion provided on the other dipoleconnector, further wherein the lock portion is elastically engageablewith the lock receiving portion only when the polarities of the plugsand sockets are the same.
 23. The connector system according to claim16, wherein the inverse connection preventing portion includes theplug-side dipole connector structure so that the plugs are offset fromeach other.
 24. The connector system according to claim 23, wherein theinverse connection prevention portion includes the socket-side dipoleconnector structured so that the sockets are offset from each other. 25.The connector system according to claim 24, wherein fitting between theplugs and sockets can be performed when the polarities of the plugs andsockets are the same, and cannot be performed when the polarities of theplugs and sockets differ from each other.
 26. The connector systemaccording to claim 25, wherein each of the plug-side and socket-sidedipole connector has a clamp, and the plugs and sockets are positionedto be stepped from of the clamp.